Lifting-jack.



R. T. NEWTON.

LIFTING JACK. APPLICATION msn $5121.20, |915.

Patented Aug. 27, 1918,

ky' IZ "/l v /lf v h o O f/V v l 46 ////.,5 I' l5 Z fig 73 v H" s n ,i I- Z" :B 1* l 3o :asy a a f@ z /0 RICHARD T. NEWTON, F NUTLEY,NE'W JERSEY.

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Specification of Letters Patent.

. .Patented Aug'. 27,1918.

Applicationled September20,1915. Serial IMQ-51,648. y

To all .whom t may concern:

Be it known that I, RICHARD T. NEWTON, a citizen of thel United `States of America,

` and residing at Nutley, in the county of Essex and State of New Jersey, have' in-v vented a certain new and Improved Lifting- Jack, of which the following is a specification.

My invention relates to liftingjacks, and the object of my invention is to provide a "simple, rugged and eflicient jack, the pawls of which are operated by a continuous rotary motion of the-operating handle, whether the jack is lifting 'or lowering the load.

In the `accompanying drawings,

Figure 1 is a side elevation, partially in section, of a lifting jack in which my in- -vention is illustratively embodied;

Fig. 2 is abroken front elevation vof the same; v n

Fig. 3 is an enlarged detail 'showing the operation ofthe pawls during the lowering of the load;

Fig. 4 is a broken partial elevation of. a

modied pawl construction; and

Fig. 5 is a broken elevation-of anoperating tool. -1

Most lifting jacks are provided with a lifting pawl supplemented by a holding pawl which engages the rack while the lifting pawl is moved downward to position to engage the next rack tooth. In such constructions the lifting pawl is actuated by a cam oscillated by a lever working back and forth through an arc in well known pump handle fashion. This type of jack, which is the one almost universally employed for liftv.

be accomplished manually from a lconvenient position to one side or back of the machine.

Referring to the drawings, and particularly to Figs. 1 to 3, the jack in which my invention is here illustratively embodied,

comprises a standard 10 with foot piece 11 and a jack bar 12 vertically guided in the standard and provided at its topV with a swive'ling rest 'orseat 13to receive the load. .A double ratchet 14 with staggered teeth is formedupon'or attached to one face .of the bar 12 and a pair j of j awls 15, 16,pass through the aperture 17 1n the standard mto engagement with the respective ratchets and.. control the vertical .movement of the jack bar in both directions. l A

These pawls are gapped at the lower ends to form bearings which rest upon the cranks 18 and 19 cut in-theshaft 20, being secured in position thereonl by pins 21 passed be-` neath the cranks between the downwardly j yextending legs'22, 23 of each pawl. The

shaft 20 1s1 journaled in side brackets 24, 25,

projecting from standard 10, andmay be squaredv at both ends, as' at 26, or have a gear 27 on lone end driven by pinion 28 the spindle of which has a squared end 29detachablyengaged with the hub of a crank handle 30.

The throwof the crank shafts 18 and 19 lis slightly greater than the length of one tooth of the ratchet 14, so that as the shaft rotates in a direction to lift the jack bar 12, the upper crank (18 in Fig. 2) carries the lifting pawl 15, while the'lower crank 19 carries the temporarily idle' pawl 16 down into position to engage its succeeding ratchet tooth. The further rotation of the shaft re- This catch lever 31 may be supported in 100 any suitable fashion, e. g., on a pivot pin 32 at the outer end .of a bracket arm 33 which also has a stud 34 to which one end of the catch spring 35 is attached. The free end of the catch lever is cut away to form a 105 shoulder 36 and ledge 37 extending to the end of the lever.k .On'the rotation of the shaft 20 in a direction to lower the jack bar 12, the leg 22 of the lower awl (16, Fig. 3)

` rides on the ledge 37 until the outward throw 110 of its crank 19 brings it against the shoulder 36, whereupon the further throw of the crank serves to tilt the upper end of the pawl out of engagement with its ratchet and hold it in this disengaged position until the now descending pawl 15 bears against the ledge 37 and depresses the catch lever 31 so that pawl 16 is freed from the shoulder 36" and v15 has slightly lifted the bar 12 and pawl 16 is thus freed from its ratchet tooth and may clear the same on its tilting movement as the crank 19 completes its outward throw.

The rack and pawl arrangement may be variously modified to accomplish the same object. Thus in Fig. 4. I have shown a single rack 38 engaged by pawls 39 and 40 of different lengths. The longer pawl 40 straddles the shorter pawl 39 and has a pair of cranks 41, 42 on the same axis but lying on opposite sides of the crank 43 for the short pawl. Save for the fact that the catch lever is wider so as to engage both legs of the pawl 40, its construction` and operation are the same as in the construction rst described.

I prefer to operate the shaft 20 by means of a long handled bit 44 (Fig. 5) provided at the end of its shank with a squared socket 45 to engage the end of the shaft. By utilizing a tool of this character, there is no necessity for getting into awkwardor dirty positions during the use of the jack.

A removable cover 46 may be provided to inclose the ratchet mechanism and protect it from dirt or injury. Where gears such as 27, 28, are used, these may also be inclosed by the cover.

Various modiiications will readily occur to those skilled in the art without departing from what I claim as my invention.

I claim as my invention 1. A lifting jack comprising a jack bar, a pawl and ratchet mechanism for operating the same, said mechanism comprising a plurality of single-tooth working pawls, and a rotary member moving said pawls into intermittent, successive, operative engagement with the ratchet on continued rotation of said member in one direction, the operative engagements of said pawls with the ratchet slightly overlapplng each other, for the purpose described.

2. A lifting jack comprising a jack bar, a

4. A lifting jack comprising a jack bar, a i

pawl and ratchet mechanism for operating the same, said mechanism comprising a plurality of working pawls, a shaft continuousl rotatable in one direction to operate the same, spring means temporarily engaging the pawls during their downward movement to press their clogging ends into ratchet' engaging position, together with catch means engaging the pawls during the pressure of said spring means when saidshaft is rotating in one direction, said catch serving to prevent the ratchet engaging movement of the pawls while under the niiuence of said spring means.

.5. A lifting jack comprising a jack bar, a pawl and ratchet mechanism for operating .the same, said mechanismcomprising a plurality of working pawls, a shaft continuously rotatable in one direction to operate the same, spring means temporarily engaging the pawls during their downward movement to press their dogging ends into ratchet engaging position, together with common catch means engaging the pawls during the pressure of sald spring means when said shaft is rotating in one direction, said catch Serving t0 prevent the ratchet-engaging movement of the pawls while under the iniiuence of said spring means.

6. A lifting jack comprising a jack bar, a pawl and ratchet mechanism for operating the same, said mechanism comprising a plupawl and ratc et mechanism for operatingthe same, said mechanism comprising a plurality of single-tooth pawls, a continuously rotatable member for actuating the latter, a spring-pressed lever lying in the path of the free ends of the pawls and temporarily engaging the latter during the non-working travelof the pawls to press the latter into t i 5 temporarilyv out ofengagemept with` the Witnesses:

ratchet-engaging 1gostion op the rotation of In 'testimony vwhereof have signed my the actuatingsha in one dlrecti'o'n, together name to this specification in the presencebf with a cate onisgid lever engagingv said twqfsubscribing Witmasses.

pawl ends and serving to hold, the pawls RICHARD T ANEWTON. .ratchet on' the rotation 'of the shaft in the RQDNEY L. MARCHANT,

opposite direction. WILLIAM ABBE. 

